Vinyl chloride resin compositions, stabilized and plasticized with epoxy compounds



United States Patent VINYL CHLORIDE RESIN. .COMPQSITIONS, STA- ggtlznig AND PLASTICIZEDWIZlH EPQXY .coM-

Paul S. Starcher, Charleston, Samuel W. Tinsley, South Charleston, and Dennis H. Mullins, St. Alhans, W. Van, assignors to Union Carbide Corporation, a corporation ofNewYork No Drawing. Application December 31, 1957 Serial No. 706,309

' 4 Claims. (Cl. 26030.4)

This invention relates ,to plasticized and heat and l ght stabilized polymer compositions an'd'has for anobject the provision of improved polymer jcompositionspin which the heat and lightstabilizers alsotact as plasticizers and thus serve as combination plasticizers and stabilizers. More particularly, this invention is directed to plasticized vinyl halide polymers and to heat and light stabilized vinyl halide polymers.

"Like manyother-resins and resin-like materials, the vinyl halide resins form thebasis of various plastic compositions in which they are associated with other substances which modify their properties in some desirable manner. For example, the vinyl resins may be compounded with various softening substances of low volatility which act as plasticizers to fo'rmsoftened compositions of increased resilience and flexibility. In common with most related compositions,-the plasticized vinyl'halide resins generally become increasingly softer and the heat softening temperature of the compositions is reduced as the amount-of plasticizers in the composition is increased. Also, it is quite usual for these softened compositions to exhibit an increased tendency toward tackiness as the quantity of plasticizer is increased, and this quality is almost invariably present when the plasticized compositions are "additionally softened by heat. The elfect of plasticizers on the physica'lproperties of finished plastic products containing the same'is indeed an important part of the success of plastic products in industry today. 1

With the increasing demand for plastic products and plastic-containing products in a-wide variety of industrial applications, many changes have been made by the plastics manufacturer to keep pace with the demand for new and useful plastic products.

High-speed, high-temperature processing of vinyl halide resin compositions, and their increasing use in outdoor applications, such as garden hose, automotive upholstery, automobile convertible tops,'agricultural irrigation accessories, agricultural goods and implements and the lkie have placed increasing demands for better plasticizers and stabilizers for use in vinyl halide resin compositions to alleviate certain shortcomings inherent in these resins. One of the most serious problems is the deteriorating effects of heat and light upon vinyl halide resin compositions. These deleterious effects aremanifested by discoloration and loss of mechanical strength of the resin composition.

In the case of plasticized vinyl halide resins, the problem may be further aggravated by instability on the part of the plasticizer and this condition may result in unsightly and troublesome exudation that has an adverse efiect on the physical properties and appearance of the composition. Exudation of the plasticizer is very often the result of alterations in the chemical structure of the plasticizer, through attack by the degradation products of the resin, or by the action of sunlight or the combined action of both. Thus, not only is there a need for adequate stabilization of the resin against the effects 2 of heat and light, but the plasticizer as well may require some protection.

On the other hand, a compound that exhibits good heat-stabilizing ability with vinyl halide resins may be relatively ineffective as a light stabilizer. For certain applications, particularly those utilizing plasticized, transparent, vinyl halide compositions, a highly desirable stabilizer would beone that. possesses ability to plasticize aswell as stabilize against bothheat and light. Some progress, in this direction, has been made in recent years with the discovery that certain epoxidized natural oils are attractive plasticizer-stabilizer combinations forgpolyvinyl chloride and some vinyl chloride-containing .copolymers but, however, it has been shown that resin compositions utilizing epoxidized natural oils are limited in their uses s'ince'these oils are not entirely compatible with vinyl chloride polymers and destruction of epoxidized natural .Oil by the degradation products of the resin causes exudation from the resin composition.

It .is'a principal object, therefore, to provide resin compositions which are markedly superior to resin compositions containing epoxidized natural oils.

It has been discovered that'this and other objects of the invention can be readily accomplished by intimately associating with vinyl halide compositions an amountof certain epoxides of 3-cyclohexene-1,l-dimethanol esters of acids and mixtures of acids comprising linoleic and/ or linolenic acids. In general, the aforesaid epoxides can be conveniently characterized according to the general formula: a

wherein R through R represent hydrogen atoms or lower alkyl groups and each of the groups separately represent an epoxyalkyl group containing 12 carbon atoms, 2n+l2x hydrogen atoms and x oxygen atoms and wherein n represents the integer l7 and x represents a whole positive integer in the range of from 2 thorugh 3.

Thus, an important embodiment of this invention is directedto compositions comprising a vinyl halide resin containing mixtures comprising the dihydroxy diesters of alcohols selected from the group consisting of 3,4- epoxycyclohexane-l,l-dimethanol and lower alkyl substituted 3,4-epoxycyclohexane-1,1-dirnethanols in which the hydroxyl groups of said alcohols are esterified by nonconjugated epoxy acids characterized by the formula:

wherein the group (C H O represents an epoxyalkyl group containing n carbon atoms,.2n+1-2x hydrogen atoms and x' oxygen atoms and wherein n represents the integer 17 and x represents a whole positive integer in the range of from 2 through 3.

Another-"novel feature and particularly important embodiment of this invention is directed to compositions comprising vinyl halide resin containing the partially epoxidized mixtures of the dihydroxy diesters of the above-mentioned alcohols and acids containing at least 2.4 weight percent .oxirane oxygen and, preferably from 2.4 to about 8.5 weight percent oxirane oxygen.

It has been discovered that not only are the epoxides, herein disclosed, useful as plasticizers forvinyl halide 2,924,ess a resins but are also useful as heat and light stabilizers as ample, methyl, ethyl, propyl, isopropyl, butyl, isobutyl,

well. tertiary butyl groups, and the like.

The plasticizers and stabilizers employed in the com- Particularly preferred S-cyclohexene-l,l-dimethanols positions of this invention are prepared by the reaction to be used in producing the novel epoxy esters of this of peracetic acid or acetaldehyde monoperacetate and a 5 invention are 3 -cyclohexene .-1,l-dimethanol and the trienoic acid ester "of 3-cyclohexene-1,l-dimethanol as methyl substituted 3-cyclohexene-1,lgdimethanols which illustrated by the following general equation, in the case include representative compounds such as 6-methyl-3- of 3-cyclohexene-1,l-dimethanol dilinolenate. cyclohexene-Ll-dimethanol.

H OHroii(CH2)4OH=CHGHCH=GH0HroH=oH(CHz)4oH3 E +7033; OOBI-v R CHzOlfiKCHB)4CH=CHOH:CH=CHCHBCH=CH(CH2)ACH3 B4 E H RI Ra R /H CHQOii(CHzhC- cHCH;C CHCH2C CH(CHz)4CH+7CH EOE 011,00(CE,)r0HoHoH,cH-oHoH,oH-0H(oHi)4CH a o I E R4 \R' H R5 The process of producing the plasticizers and stabi- The fatty acids can be derived from any animal, lizers is carried out at temperatures in the range of from vegetable or marine oil containing linolenic acid. The C. to 150 C. At lower temperatures, the rate fatty acid group can be the mixed fatty acids in such of epoxidation is slow. At higher temperatures, the rate oils. Typical oils which can be employed include cottonof epoxidation is faster, but precautions are necessary seed oil, linseed oil, perilla oil, rapeseed oil, safflower oil, to prevent the further reaction of the epoxide groups. and soybean oil. If desired the linolenioor linoleic acids Temperatures in the range of from 10 C. to 90 C. are can be isolated in the pure state although that is not preferably used to provide a suitable reaction rate and necessary. In fact it is sometimes desirable to employ to avoid undesired side reactions. The olefinically unthe mixed fatty acids directly because of ease of handling saturated starting material is conveniently charged to a and cost. reaction vessel and the theoretical quantity of peracetic The fatty acid or mixture of fatty acids are esterified acid is then added. Seven or more mols of peracetic in a conventional manner with an appropriate 3-cycloacid per mol of olefinically unsaturated compound are 3 hexene-l,l-dimethanol to provide the starting material usually added to the olefinically unsaturated starting mafor e'poxidation as aforesaid. terial. Both types of double bonds in the molecule are 40 The degree of protection that these novel plasticizer relatively easily attacked by the peracetic acid and the and stabilizer epoxides confer upon vinyl halide resin epoxidation of both types appears to proceed simultanecompositions is relatedto the concentration of the epoxy ously. The reaction is allowed to proceed until approxicompound in the resin composition. It has been dismately the theoretical amount of peracetic acid is concovered that as little as 0.5 percent by weight based on sumed, which is determined by periodic tests for perthe resin of the epoxide will confer desirable, beneficial acetic acid. The time of reaction is usually from about effects upon the vinyl halide resin composition. one to ten hours, depending on the temperature. In It has also been discovered that the epoxides can be working up the crude reaction product, it is preferred, used alone or in conjunction with other plasticizers. although not absolutely necessary, to separate the by- Whenit is desired to use the epoxide as a plasticizer, product acetic acid from the epoxide rapidly, since the it has been discovered that the amount of epoxide is not by-product acetic acid will react with the epoxide to narrowly critical. As little as 0.1 part by weight (0.1 form undesired products thus decreasing the overall yield percent by weight) of epoxide per hundred parts of resin of triepoxide pr duct. The reaction mi u is t Sllh- I will impart a noticeable difference in the desired degree jected to conventional recovery. procedures for the reof flexibility and confer some protection against ernbn'ttlecovery of the epoxide product. The product an be rement at low temperature and the degradative effects of covered by extraction with a suitable solvent; continuous exposure t he t a d light, H eve th majority of distillation OI distillation under reduced pressures as deplasfioized vinyl chloride resin compositions are based sired, or a residue product may be taken. on mixtures of plasticizers in order to obtain the desired Th 3-eyeleheXene-1,l-dimethanels are in d y the properties in the finished items and it has been found re of the COITBSPOHdiHg 3-cyclohexfillecafhoxaldethat the epoxides disclosed herein can be used effectively y (P p y the Dials-Alder reaction of butadiene 6 in conjunction with conventional plasticizers. The presor a substituted butadiene with acrolein, crotonaldehyde, ence of these b id dd measurably to h h d and the like) With excess formaldehyde in the l light stability of. the vinyl halide resin composition in of a base catalyst such as KOH as described y addition to contributing towards the flexibilizing of these French and D. M. Gallagher in J.A.C.S., 64, 1497 iti A Variety f cycloaliphatic aldehydes Suitable Where stabilization of a vinyl halide composition is reaction with formhldehyde to m wrrespond' the primary objective, with little or no interference with ing 3'cyclohexenell'dlmettianoli can Produced other properties, concentrations of epoxides in the range ing alkyl substituents contained 1n the ring when comof from L5 to 8 parts by Weight per hundred parts of Pounds. Such as amok-in i croionaldehydgare reacted resin have been found to be adequate. In specific appliwfthl dlenes Such butadlene pllierylene .lsop cations requiring freedom from color drift during processdrmethyl-LB-pentadrene and the llke.

The preferred 3 cyclohexene l,Ldimethanols which ing, such as in transparent films, it is sometimes necessary contain alkyl groups attached to the cyclohexenyl ring l 115}? lh 'y adm1ufT1-I1ta1111hg StahlhZeIS In 6 are-those with alkyl -s ubstituents having frorn'on'e to luhcllon Wlth the ePOXIdCS- A150, It has been found four carbon atoms in the alkyl chain such as, for exthat synergism is exhibited when cadmium-barium comroll mill.

deter poundslare-lusedeimconjunctionwith ctheepoxides in resin' compdsitionsnw. e e M -F11 e. winyI. ihalide ,tresins' \whieh can be satisfactorily.

plasticized and stabilized by the ,epoxides herein disclosed can be any vinyl halide polymer such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, vinyl chlonde-acrytonitrile lcopolymers, vinyl"chloride-vinyfidene chloride copolyiners, vinyl 'chloride-vinylidene chloride- 9 1 rue copclymers- Prefe red. nyl ha e resin resins and resins containing ers: of this nvent o may ot er pl sti izers n vinyl c ions tojobtain the desired results. It is'parploy these .;plasticizers and h 9th?! commercial plaspermits the j obtainment or r. ugh th j in eet a rel- Q ah h yelfi eut, m reexpen i n u s1 tab l z e ,a a el ti y large .Llss ei c e tless. xpensive c m rc a er without sjagri cin'gthe desired effectspfAs noted 'hereinbefore, the incorporation of epoxides, disclosedherein, into vinyl halide. compositions, in conjunction with cadmium and cadmium-barium compounds produces -a synehgjisticstabilizing effect. In-other words, the

stabilizing efte ct' produced b y the use of two different substa cs' in combination 'is considerably greater than either substance alone. Y i

{I "'iprep a ring specimens for evaluation of the compositionsfor flexibility,'re sistance to .embrittlement atlower temperatures and resistance to thedeteriorative effects o f heat and lightga basic recipe comprising a vinyl halide resin is mechanically mixed'with various amounts of the epoxy compounds, defined by the general formula set fi h above with or without a supplementary plasticizer 'shgh spdioctyl'phthalate and the resulting mixtures fluxed and milled on a heated, laboratory, ,difierential speed twoth'efsum f the stabilizing effects expected from use of tained at 158 C. generally but higher temperatures, in

" the neighborhood of 170.. vC. .can .be employed.

The surface temperature of the 'rolls is main-' The heat-stabilizing ability oftthe epoxy compounds is N e I ed, by both static and dynamic methods. When the heat-stabilizing" ability is to be determined by the static method, sainples of the fluxed sheet are mounted M 1 ;.Ill11S-Ll..WiI6 meshs'cr en and placed'in V circulating air oven wherein the temperatureis maintained at about 158 CS. Samples arethen withdrawn at" pproximately thirty rninute intervals and discolorato. Florida. The specimenswere,mounted, with no sup- L -forty-fivedegree angle from the h r i-, r o r tal facing} south. The exposure time is recorded in urea Sun-ho r being c mu p od f ty:

urin --W ic.h ad an ne y m u to v 0,8 2 3 gramgcalories per square centimeter per .s. Cl ppiu s rom h exp e e p exiniue r af er; many sun hours, to de min w er shor om s uch as. di c l r on. sp n stiffeningfor.

I exudation had been induced by exposure to sunlight. An

' tro with respect to the, original sheet, is. determined by .I "means of a Photovolt Reflection Meter, Model 610. equipped with a Wratten' C- SbIue filter.

excessive edegree soflany .one ior :a combination of these shortcomingsqconstitutes .failure. W

In determining the plasticizing ability :of the various epoxy compounds, amounts. of the .epoxideare iHCOIPO.

rated into :the vinyl chloride resin composition which wouldimpartan arbitrary flexibility to the vinyl chloride resin composition. In this case, the selected flexibility was .a modulus :of 11090 pounds .per square .inchat percent elongation as :read from a stress-strain curve determined at 2.4.5 C. onna Scott L-6 tensile tester operating :at a :constant rate .of elongation of four feet per :minute. .The amount ofithe epoxide required-to impart the. desired degree of .fiexibility is listed as the effectiveness in parts per 100 parts of resin. Mixtures of vinyl chloride resin composition and epoxy compound are fluxed for fi-ve minutes at 158 C., and samples from the resulting milled sheet-were then compression molded forten minutes at 158 C. to form suitable samples for testing. I i 1 in reporting the results .of the evaluation ofthe -com-. position certain symbols and abbreviations have been employed for the sake of simplicity and brevity. Accordingly, the following :test methods, symbols, and abbreviations, .asusedin the examples, are defined as l ow (a) AsTM fAmerican Society of Testing Materials. b) T -and T =points corresponding to 135,000 and [10,000 pounds per square inch respectively on a stiffness-temperature curve obtained in accordance with I the procedure set forth in the manual of ASTM D1043- .51. t (c) Brittle temperature (T =the temperature obtained bymeans of low 'temperatureimpact test according to the; procedure set forth inuthe manual of ASTM D746- .52T,.j

d) .SPI volatility loss=value obtained in accordance: .with the procedure .in the manual of ASTM D1203- '52T. I

( e).Duro meter A. hardness=an indentation measurement of hardness obtained with the Shore Durometer, A head.

(I) Sweat out=visual andmanual examinations to detect i any exudation of plasticizer that may appear as heads,

a smear or a blush on the surface of the plasticized material. The observation is made after two weeks .-of aging at 25 C. i

..(g) Instron. stifiness modulus=one hundred times the stress required to elongate a sample one percent as measured on an Instron Tensile Tester at room temperature (24 C f.j).

(h) Accelerated oil and water extraction:

Oil=Films 4-mils thick and mounted between beds of glass beads and covered with preheated mineral oil; The test is runat 50 C. for a time sufiicient to. obtain between 3 and 10 percent weight loss-.- Oil extraction constant k is calculated from:

1 a W =original weight (g.) W =final weight g.)

- a=total area (square meters) t=time (hours) Water=Films 4-mils thick are mounted. between beds of water-washedactivated carbon and covered with distilled water. C. for 24 hours. Percent weight loss of the films at the end of the test period is recorded.

' The following examples will. serve to illustrate the practice of the invention.

EXAMPLE 1 Ll-dimethan ol A mixture of71 grams of 3 cyclohexene-l,l-dimetha The test is run at 7.0

- perature of 70 201 C.) until water evolution had ceased (13 hours); The residue product was washed with hot Water and stripped of volatiles and excess acid to a temperature of 210 C. at 8 mm. pressure. The residue product, the

linseed fatty acid ester of 3-cyclohexene-1,l-dimethanol was characterized by the following properties:

Color No. 12 Gardner Acidity 0.219 Saponification equi 3l2.9 Iodine No 193.5 Density /20 0.9475

EXAMPLE 2 Preparation of 3,4-epoxycyclohexaneJ,I-dimethlmol bis- (9, 10, 12, 13, 15, 16-triepoxystearate) I A solution (298 grams) of 28 percent peracetic acid (1.1 mols) in ethyl acetate is added, with stirring, over a period of 45 minutes at a temperature of 50C. to 95 grams (0.143 mol) of 3-cyclohexene-1,1-dimethanol'dilinolenate. Stirring is continued for an additional 4 hours whereupon analyses for peracetic acid indicated that consumption of peracetic acid had substantially ceased. fiThe reaction mixture is fed dropwise to the kettle of a still containing ethylbenzene under reflux at such a pressure as to maintain a kettle temperature of 50" C. Ethyl acctate, acetic acid, and ethylbenzene are removed continuously. After the addition is complete, the kettle material is stripped of volatiles by keeping it for 2 hours at a tem- C. under a pressure of 1 mm. while allowing a very slow stream of nitrogen to beadmitted summarized in thefollowing Table 1:

benzene are removed continuously. After' .-the' addition is complete, the kettle material is stripped of volatiles by'heating for 3 hours at70" C. at 2 mm. pressure'in a slow stream of nitrogen. pi

7 .i Preparation of epoxidized linseed oiMz'cid diesterspf 3-' cyclohexene-I,l-dimethartol A solution of 2.4 mols of peracetic acid in ethyl acetate? is added dropwise to 275 grams. of the linseed oil fatty'f acid ester of 3-cyclohexeneal,l-d'imethanol 'overa, period of l hour and 55 minutes while the temperature is r'naintained-in the rangeof from to C. Stirring is; continuedfor an additional 2 hours and 25 minutes whereupon an analysis for peracetic acid indicates that the reaction had proceeded substantially tocompletion. The reaction mixture is then stored at 11 C.'for a period of 1'6'hours. The residue product is' then purified by re'-, moving ethyl acetate, acetic acid and other volatilesandi there is provided 311 grams of a light amber liquid hav-. ing an oxirane oxygen content'of 8.23 percent, aniodinel'. value of 4.6 anda color of 6 Gardner. 1 I

EXAMPLE 5 Recipes were prepared to test the performance of the epoxidized linseed oil fatty acid diesterof 3-cyclohexene-= 1,1 dimethanol having an oxirane oxygen content of 8.23 percent as a heat and light stabilizer for agvinyl halide resin. The recipes comprised 100parts of a vinyl chloride-vinyl acetate polymer resin containing from 96 to 98 percent vinyl chloride, various amounts of'a commercial plasticizer, dioctyl phthaIate, and various amounts of the aforementioned epoxide The amounts employed in the tests are reflected in Table 1. a

All of the recipe compositions were'subjected to heat and light stability tests in accordance with the procedures hereinbefore described. The results of ,the tests TABLE 1 Composition (parts) Mill Stablllty-Mlnutes'at i Initial 170 O.to Florlds Test No. BLR, Exposure Percent Y Sun-hours; Resin Dloctyl Epoxy 80% 75% 40%. to Failure- Phthalate Compound BLR BLR BLR BLR.

EXAMPLE 3 Preparation of 3,4-epoxycycl0hexane-LI-dimetltartol bis- (9, 10, 12, 13-diepoxystearate) .A solution (363 grams) of 23 percent peracetic acid (1.1 mols) in ethyl acetate is added with stirring, over a period of 1 hour at a'temperature of 50 C. to 133 grams (0.2 mol) of 3-cyclohexene-1,l-dimethanol dilinoleate. The reaction is continued at the same temperature for an additional 3.5 hours, whereupon an analysis for peracetic acid indicated that the reaction had proceeded substantlally to completion. The reaction mixture is fed dropwise to the kettle of a still containing ethylbenzeneunder reflux at such a pressure as'to maintain a kettle temperall? O250 Ethylacetate, acetic acid, andethyl- As may be observed, the employment of various amounts of epoxide conferred some improvement-in; heat stability of the resin compositions."

It may be also observed that the 'heat and light stabilizer of Example l is compatible with commercial type plasticizers such as dioctyl'phthalate. 1

. EXAMPLE 6 Arecipewas prepared containing partsofthe resin described in Example 1, 0.5 percent 'byweight of dibutyl tin maleate vas a stabilizer and amounts of the epoxidized linseed oil fatty acid diesteroffl'3i-cyclo hexene-1,1-dimethanol having an oxiraneoxygen con tent of 8.23 percent; as indicatedin Table 2. The composition was fluxed on a heated differential two-roll 'mill. The surface temperature of the'rolls was maintained at 158 C. After'a period of flve minutes'the flux con-- tents were removed from the mill and strips of the approximately 30 mil'sheet were mounted'on a stainless steel wire mesh screen which was then placed in a circu lating oven maintained at a temperature'ofi 158 C. ;'Ihe

strips were removed from the oven at minute intervals and discoloration, with respect to the original sheet,

was noted. The discoloration was measured by means TABLE 2 Plasticizer, p.p.hr. 52 Plasticizer, percent 34.0 Tensile, p.s.i. (24.5 C.) 2730 Elongation, percent (24.5" C.) 250 7 Load at 100% elong., p.s.i. (245 C.) 2400 ASTM Instron stiffness modulus, p.-s.i. (24.5 C.) 5800 T C. 7 T C. 24 Brittle temperature, C. 8 Extraction:

Oil, K, C. 0.4 Water, percent in 24 hours at C 1.4 Durometer A hardness (24.5 C.) 89

SP1 volatile loss, percent in 24 hours at 70 C. 0.3 Heat stability-data:

Initial color, percent BLR 72 Min. at 158 C. to 80% BLR Min. at 158 C. to 75% BLR What is claimed is:

1. A vinyl chloride composition comprising a vinyl t0 chloride resin containing epoxidized diesters of 3-cyclohexene-1,1-dimethanols characterized by the formula:

wherein R through R represent members selected from the group consisting of hydrogen atoms and lower alkyl groups and the group (C H O represents an epoxyalkyl group containing n carbon atoms, 2n+l-2x hydrogen atoms and x oxygen atoms wherein n represents the integer l7 and x represents a whole positive integer in the range of from 2 through 3.

2. A vinyl chloride composition comprising a vinyl chloride resin containing 3,4-epoxycyclohexanel,l-dimethanol bis(9, 10, l2, l3, 15,16-triepoxystearate) 3. A vinyl chloride composition comprising a vinyl chloride resin containing 3,4-epoxycyclohexane-l,l-dimethanol bis(9,1 0,12,13-diepoxystearate).

4. A vinyl chloride composition comprising a vinyl chloride resin containing the epoxidized linseed oil fatty acid diesters of S-cyclohexene-l,l-dimethanol.

References Cited in the file of this patent UNITED STATES PATENTS 2,786,067 Frostick et al Mar. 19, 1957 

1. A VINYL CHLORIDE COMPOSITION COMPRISING A VINYL CHLORIDE RESIN CONTAINING EPOXIDIZED DIESTERS OF 3-CYLOHEXENE-1, 1-DIMETHANOLS CHARACTERIZED BY THE FORMULA: 